Most of the folks I talk to feel that Juul is bad because of it's addictive properties, which I suppose in a way is a testament to it's efficiency in delivering nicotine. I also use pods for the same effect, but it was the Juul that got me seriously started on high-nic devices to stop my cravings.
When I use a mod and RDA with 6mg juice I seem to chain-vape all day and still want a smoke.
...and I want to reiterate that the Juul will never be my primary device - I agree that it is expensive and proprietary, and not a fan of that in computers either.